An 11 mu W, Two-Electrode Transimpedance Biosignal Amplifier With Active Current Feedback Stabilization

作者：Inan Omer Tolga^*; Kovacs Gregory T A

来源：IEEE Transactions on Biomedical Circuits and Systems, 2010, 4(2): 93-100.

DOI：10.1109/TBCAS.2009.2032096

• Biosignal amplifier
• electrocardiogram
• portable physiological monitoring

A novel two-electrode biosignal amplifier circuit is demonstrated by using a composite transimpedance amplifier input stage with active current feedback. Micropower, low gain-bandwidth product operational amplifiers can be used, leading to the lowest reported overall power consumption in the literature for a design implemented with off-the-shelf commercial integrated circuits (11 mu W). Active current feedback forces the common-mode input voltage to stay within the supply rails, reducing baseline drift and amplifier saturation problems that can be present in two-electrode systems. The bandwidth of the amplifier extends from 0.05-200 Hz and the midband voltage gain (assuming an electrode-to-skin resistance of 100 k Omega) is 48 dB. The measured output noise level is 1.2 mV(pp), corresponding to a voltage signal-to-noise ratio approaching 50 dB for a typical electrocardiogram (ECG) level input of 1 mVpp. Recordings were taken from a subject by using the proposed two-electrode circuit and, simultaneously, a three-electrode standard ECG circuit. The residual of the normalized ensemble averages for both measurements was computed, and the power of this residual was 0.54% of the power of the standard ECG measurement output. While this paper primarily focuses on ECG applications, the circuit can also be used for amplifying other biosignals, such as the electroencephalogram.

• 出版日期2010-4